1. Field of the Invention
The present invention relates generally to collagen and gelatin compositions and methods for their preparation and use. In particular, the present invention relates to a gelatin film having characteristics suitable for application to tissue for a variety of purposes.
The use of biological materials for the sealing of wounds and other defects in tissue as well as the inhibition of tissue adhesion has been proposed. For example, the use of collagen patches for closing wounds and creating an anastomoses has been suggested in U.S. Pat. Nos. 5,071,417; 5,156,613; 5,209,776. U.S. Pat. No. 5,156,613, is assigned to the Assignee of the present application, and describes the immobilization of collagen-containing patch material to tissue using radio frequency and laser energy.
Numerous procedures and materials have been proposed to minimize or eliminate post-surgical adhesions. Such procedures include introducing barrier materials such as metals, polymers, and natural materials over the target site. A woven material of regenerated cellulose is currently marketed for this purpose by Johnson & Johnson under the trademark Interceed.RTM.. A film of hyaluronic acid is also available under the trademark Seprafilm.TM. (Genzyme Corp, Cambridge, Mass.) This product, however, is not attached to tissue and remains unfixed in vivo. Other polymeric materials that have been tried for this purpose include nylon, cellophane, PTFE, polyethylene, siloxane, elastomers and polylactic acid copolymer films. Many of these materials are not biodegradable and therefore, remain in the body with unpredictable and potentially undesirable consequences.
Of particular interest to the present invention, gelatin or collagen films have been applied to tissue for tissue sealing. Specific gelatin materials are described in parent application Ser. Nos. 08/303,336 and 08/481,712, the full disclosures of which have previously been incorporated herein by reference.
To be effective for use over tissue in order to seal the tissue, prevent adhesion, or for any other purpose, collagen or gelatin films should possess a number of characteristics. They should be sufficiently thin so that they can be effectively bonded to the underlying tissue by the subsequent application of energy. They should be sufficiently pliable so that they can conform to the tissue, further enhancing bonding to the tissue upon subsequent application of energy. They should possess low moisture, enhancing their preservation and permitting rehydration upon application to tissue. They should be sufficiently elastic, still further enhancing conformability to tissue. They should be sufficiently strong so that they can be bonded to tissue and can provide the desired sealing after bonding. They should possess melting temperatures which facilitate fusion and bonding to tissue upon the application of energy. Different embodiments of the present invention will meet at least some of these objectives.
2. Description of the Background Art
WO 93/17669 describes particular hydrogel materials that may be applied to tissue, cross-linked by exposure to UV, and relied on for inhibiting tissue adhesion. U.S. Patents relating to materials and methods for inhibiting tissue adhesion include U.S. Pat. Nos. 5,422,376; 5,410,016; 5,380,536, 5,366,735; 5,364,622; 5,365,883; 5,321,113; 5,266,326; 5,264,540; 5,194,473; 5,156,839; 5,135,751; 5,134,299; 5,126,141; 5,068,225; 5,017,229; 4,937,270; 4,937,254; 4,911,926; 4,889,772; 4,674,488; and 4,603,695. Published PCT applications relating to materials and methods for inhibiting tissue adhesion include WO 95/15747; WO 95/15343; WO 95/09883; WO 94/24962; WO 94/21324; WO 94/08635; WO 94/02517; WO 93/16687; WO 93/13137; WO 92/22312; and WO 92/21354. Published European applications relating to materials and methods for inhibiting tissue adhesion include 669 138; 645 150; 610 731; 608 921; 608 139; 426 368; 416 250; and 372 969. Other patents relating to applying energy to fusible materials to wound treatment include U.S. Pat. No. 5,071,417; U.S. Pat. No. 5,156,613; and U.S. Pat. No. 5,209,776. Co-pending related applications assigned to the assignee of the present application include U.S. Ser. Nos. 08/303,336; 08/461,227; 08/461,228, 08/481,712; and 60/011,898, the full disclosures of which are incorporated herein by reference. Application Ser. Nos. 08/303,336 and 08/481,712, were published on Mar. 14, 1996, as WO 96/07355 and WO 96/07356, respectively.